table {
    border-collapse: collapse;
    width: 80%;
    text-align: left;
    margin-left: auto;
    margin-right: auto;
    margin-top: 5%;
    background: rgba(255,255,255, 100%);
}

table,
th,
td {
    border: 2px solid black;
    padding: 20px;
}


.but_Retour {
    border-radius: 3px 3px 3px 3px;
    padding: 10px;
    margin-top: 10px;
    padding-bottom: 10px;
    border: none;
    font-size: 20px;
    text-align: center;
    font-style: oblique;
    transition: all 300ms ease-out;
    background-color: orange;
    flex: 1;
    text-align: center;
}

.but_Retour:hover,
.but_Retour:focus {
    background-color: black;
    color: white;
}

.center {
    text-align: center;
}